1. Field of the Invention
A high speed lens grinding and polishing machine comprising a lap tool holder and lens blank holder including independent means to provide linear and rotary movement between a lap tool and lens blank.
2. Description of the Prior Art
Numerous devices have been developed for grinding and polishing lens blanks for producing a compound curvature surface. Generally the lens blanks are ground to a predetermined toric shape and then polished with a lap tool having a curvature corresponding with that to be imparted to the finished lens.
In surfacing operations, alignment axes of the lens blank and lap tool is critical. To maintain proper alignment various complex elaborate structures to support the lens blanks and lap tools have been developed. Unfortunately the complexity of such devices present poor lens quality when operating at relatively high speeds. Generally existing machines fall into one of two groups. The first group shows various spring biased operable support shafts in combination with various lens support working tools. These devices disclose grinding and polishing machines employing a biasing spring to urge the work piece and lens upward against the grinding/polishing tool itself. The second group shows a number of polishing machines including movable linkages or spring biasing means attached to the upper portions of the machines or mechanism which urge the cutting or grinding tool into operative engagement with the lens or mirror surface.
Since the time required to produce a polished surface is dependent upon the relative movement between the lens blank and lap tool existing devices designed for low speed operations are inadequate. Other factors affecting the effective operating speeds are the initial lens blank surface, the pressure applied between the lens blank and the lap tool and the polishing medium.
Present devices and techniques have not been able to meet the increased requirements for more accurate and efficient production methods without sacrifice of lens quality. This is particularly true due to the problems of balance and vibration in the interface between the lens blank and lap tool during high speed operations.